I am a new rider and am confused about something I read. When I first went out riding, I shifted the bike whenever I thought it was sufficient to. I didn't pay attention to RPM's or anything like that...just listened to the bike. I have the Kawasaki GPX250R which has a redline of 14k. I never get that high but I know it is there. I generally cruised around at 4-5k RPM unless I needed to go up a hill. This is my first bike and obviously I cannot help but compare the way RPM's sound to a car. I read on the Ninja 250 wiki pages that the engines on this bike like to run fast and it was suggested to shift in the 6k-10k range which I have no problems with. What confused me, is that is said to never cruise below 6k. I understand that is is good to stay in a high RPM range so you have some power to get out of a situation, but it just seemed like a lot of revs and noise just to cruise along...not to mention possibly using more fuel. Can anyone more experienced explain to me what a good rule of thumb is? I will be commuting each day and get reasonable fuel economy. Thanks.